1. Field of the Invention
This invention relates to a sheet loading device for causing sheets (cut sheets or paper leaves) put out one after another from a sheet output apparatus such as a laser beam printer or a copying apparatus onto a sheet receiving member to be loaded in orderly, mutually superposed relationship without being deviated from one another.
2. Description of the Prior Art
An apparatus such as a laser beam printer which puts out a great quantity of sheets generally has at the sheet output portion thereof a sheet loading device (a stacker) provided with sheet aligning mechanism.
FIG. 1 of the accompanying drawings is a perspective view showing the essential portions of an example of such device. Reference numerals 1 and 1 designate a pair of sheet discharge rollers provided on the side of a sheet output apparatus such as a laser beam printer, not shown, and reference numeral 2 denotes an output sheet supporting bed as a sheet receiving member disposed in front of the pair of sheet discharge rollers. Sheets P are discharged one after another onto this supporting bed 2 and piled thereon. The supporting bed 2 is initially raised to a level slightly lower than the sheet output portion of the pair of sheet discharge rollers 1 and 1 by a vertically moving mechanism, not shown, and it is automatically lowered little by little as the piling of sheets progresses, and can support thereon a great quantity of sheets before it reaches its lowermost limit of downward movement.
The sheet aligning mechanism serves to bring the sheets discharged one after another onto the bed 2 into an orderly piled condition and comprises a pair of sheet guide bars 3 and 3 vertically disposed as discharged sheet front side positioning members on the front side of the sheet supporting bed 2, a pair of paddles 4 and 4 disposed between the pair of sheet guide bars 3 and 3, a sheet guide plate 5 vertically disposed as a discharged sheet left side positioning member on the left side of the sheet supporting bed 2 and parallel to the left side edge of the bed 2, and a putter 6 disposed on the right side of the sheet supporting bed 2. These members 3-6 are positioned and supported on an immovable member, not shown.
The sheet guide bars 3 and 3 and the sheet guide plate 5 are disposed in a relation in which a plane containing the sheet guide bars 3 and 3 and a plane containing the sheet guide surface of the sheet guide plate 5 intersect each other perpendicularly to each other.
Each of the paddles 4 comprises a rotary member 41 and a plurality of radially extending vane members 42 formed of a flexible material such as rubber sheet strips or the like and mounted around the rotary member 41, and may be rotatively driven in the direction of arrow by a motor 43 through a shaft 44, whereby the vane members 42 are rotated in friction contact with the upper surface of the piled sheets on the bed 2 in such a manner that they strike said upper surface, and thus, a gathering force toward the sheet guide bars 3 and 3 acts on the uppermost one of the piled sheets on the bed 2.
The putter 6 swings to right and left about a vertical shaft 62 with the intermittent supply of power to an electromagnetic solenoid-plunger 61 and strikes the right side edge of the piled sheets P on the bed 2, whereby a gathering force toward the sheet guide plate 5 acts on the piled sheets P on the bed 2.
Thus, the sheets P discharged one after another onto the bed 2 are positively gathered toward the sheet guide bars 3 and 3 which are the sheet front side positioning members by the paddles 4 and 4 and the front side of the sheets strikes against the sheet guide bars 3 and 3 and the sheets become positioned thereby. Also, the sheets are positively gathered toward the sheet guide plate 5 which is the sheet left side positioning member by the putter 6 and the left side of the sheets strikes against the surface of the sheet guide plate 5 and the sheets become positioned thereby. Thus, the individual discharged sheets P are piled on the bed 2 in orderly, mutually superposed relationship with the sheet guide bars 3, 3 and the sheet guide plate 5 as the sheet front side and left side positioning members.
Now, to enable the above-described sheet loading device to be used correspondingly with various sheet sizes, the sheet guide plate 5 which is the sheet left side positioning member may be fixed, but the sheet guide bars 3, 3 which are the sheet front side positioning members, the paddles 4, 4 and the putter 6 must be designed to be movable and adjustable in position. However, the entire device becomes complicated and its operability is poor when the members 3, 3, 4, 4 and 6 are designed to be movable in two different directions and adjustable in selected positions.
Also, the loading device of this type has heretofore been constructed as follows:
(1) The output sheets are loaded onto the pallet;
(2) The pallet is vertically movable by a lift device to keep the supporting surface constant;
(3) When a predetermined quantity of sheets has been loaded, the lift device is lowered to its lowermost limit;
(4) That condition is a condition in which the sheets and the pallet have become contained in the container; and
(5) The container is installed on a bed which can be drawn out, and the bed may be drawn out and the container with the sheets and the pallet contained therein may be removed and carried.
Such construction has led to the undesirable possibility that during sheet loading operation, the bed may be drawn out by mistake and the sheets become jammed. Also, the container must be set on the bed while containing the pallet therein, but when the operator forgets to place the pallet into the container, the sheets may again become jammed and this has sometimes led to the undesirable possibility of damaging the device.